The Purana narrates that a Brahman may take four wives, a Kshatriya may have three wives, a Vaishya will have two and a Shudra on the other hand can have only one wife. It has been said that sacrifices and religious ceremonies cannot be performed by a husband in front of a wife not belonging to the same caste. On the other hand a wife of the same caste has that privilege.
Lord Agni has described that a Kshatriya woman after her wedding should hold an arrow in her hand; a Vaishya bride should hold a paddy measure while a Shudra girl should hold a cotton string in her hand just after she has gone through the wedding ceremony. It has been mentioned that a girl can be given away only once in marriage. And a man who robs or carries away a married girl is considered a thief.
The Purana mentions that only under certain conditions can a woman marry for a second time. The conditions are namely moral degradation of her husband, his death, renunciation by him of all worldly pursuits, his resorting to a monastery. It has also been said that a widowed woman may marry the brother of his husband or as an alternative she may marry anyone of her choice.
The God of Fire in his description of the various rites involved in marriage says that a man should not marry a woman belonging to his own Gotra or from a family acknowledging the leadership of the same Rishi as his own. At the same it has been mentioned that marriage with a woman is not forbidden where the bridegroom is not related to her within seven degrees in the father's line or five degrees on the side of the mother.
Besides the several regulations involved in various forms of marriage, the Agni Purana has also explained the different forms of marriage. The Brahma Marriage is characterized by the giving away of the bride to man of good and noble parentage and possessed of excellent virtues and who has been specially invited and requested by her father for that purpose. This sort of marriage is in fact considered as the best form of uniting a man and a woman in holy wedlock, as it is supposed to carry the bride's forefathers to heaven.
In the Arsha Marriage the bride is given away with the presents of a couple of bullocks to bridegroom, while in the virtue giving Prajapatya Marriage, the bridegroom or his relatives on his behalf ask for the hands of the bride. The other forms of marriage which have been mentioned in the Purana are the Asura Marriage, the Gandharva Marriage, the Rakshasa or the Paishacha form.
Another important aspect which has been narrated by Lord Agni in the Agni Purana is that there are auspicious as well as inauspicious phases and a marriage ceremony should be considered during the auspicious phase keeping in mind the favourable planetary positions. The favourable periods of considering a marriage ceremony are the asterism of Soumya, Pitrya, the Vayavya, the Savitra, the Rohni, the three Uttaras, the Mula, the Maitra and the Pushya.